There are many applications in which an external electrical interface is required for an electrical device. An external electrical interface is generally required for the provision of power to the device and to provide communications between the device and other electrical devices. Numerous techniques are known in the art for electrically interfacing to a device. One such technique, common to batteries and portable electronic devices, is the use of an electrical contact accessible through the device housing.
Electrical contacts have been traditionally formed using discrete contact elements electrically coupled to circuitry within the device. For example, a portable two-way radio may include a radio portion and a battery portion. The battery portion typically includes discrete electrical contacts for electrically interfacing with a battery charger, in addition to contacts for electrically interfacing with the radio portion. For example, U.S. Pat. No. 5,006,073, issued to Mennona, Jr. on May 15, 1990, for a Snap Fit Contact Assembly, discloses a device in which discrete electrical contacts are soldered to a flexible film substrate and then positioned within a housing. Electrical connection is provided between the contact and electrical circuitry within the battery, thus completing the external interface. Alternatively, the discrete contacts may be affixed directly to a circuit carrying substrate used in the internal operations of the battery. The contact may be soldered to the substrate, or affixed to the substrate using rivets, and the like, and is made externally accessible through openings within the housing.
However installed, the use of discrete electrical contacts in the design of external electrical interfaces has several drawbacks in product manufacturing. For example, there is significant time and cost involved in the design and development of contacts for a given product. Moreover, tools to produce the contacts must be designed and developed, which adds to the overall cost of the product. Thus, product development cycle time and cost are adversely affected by the use of discrete electrical contacts.
There are also manufacturing issues related to the use of discrete contacts in a product. Specific manufacturing operations must be designed to position the contacts during product assembly, to establish the proper electrical connections between the contacts and circuitry within the product. These operations, which include contact alignment and contact soldering, may require expensive tooling and other equipment, or may be labor intensive, and can be a contributing source of defects in the product. Thus, there is a penalty in manufacturing efficiency for products using discrete contacts.
Additionally, the use of discrete electrical contacts adds weight to a product, increases material costs, increases the number of parts required in a product, and increases inventory as stocks of these contacts are needed to facilitate production. These and other problems become more acute as product designers focus on reductions in costs, size, and weight, in the design of battery packages and other applications.
There are several benefits inherent in the use of electrical contacts to achieve external interfacing between electrical devices. Some of the more obvious benefits include the simplicity and convenience of establishing the interface. However, the costs associated with the above-mentioned problems are undesirable. As such, an improved interface design is needed, which avoids the problems associated with discrete electrical contacts while retaining the benefits of this type of external electrical interfacing.